This invention relates to a cleaning plug assembly of the type used in cleaning the interior of condenser and heat exchanger tubes and the like, the plug assembly being adapted to be propelled through a tube by pressurized fluid injected into the tube.
To clean condenser and heat exchanger tubes, and the like, it is common to use plugs, sometimes referred to as pigs, which are propelled through the tubes by pressurized fluid. The known plugs are provided with scraper elements such as blades or brushes fixed to an elongated body such that the scraper elements contact the inner walls of the tubes. Problems have existed with the heretofore used plugs in that in some instances they do not provide effective contact between the scraper elements and the tube walls resulting in less than complete cleaning, and in other instances the scraper elements experience rapid wear necessitating frequent replacement of the entire plug at unnecessary expense. Other plugs are complex in their structure and thereby expensive, along with being oftentimes subject to rapid wear and ineffective scraper element-to-tube wall contact. With virtually all of the existing cleaning plugs the scraper elements are sized for use with certain sized tubes and make no provision for replacement of different sized scraper elements for use with different sized tubes.
This invention overcomes the heretofore inherent problems of existing cleaning plugs by providing a new and unique cleaning plug assembly which has an effective scraper element-to-tube wall contact, is simple in structure, and allows the use of different sized scraper elements on a single plug body for use with different sized tubes. Additionally, the cleaning plug of this invention allows for passageways in its body for receiving and directing fluid to aid in propelling the plug through a tube and for discharging into the tube to assist in the cleaning process. Also, the present cleaning plug may be formed of flexible materials capable of bending or flexing and resuming its original shape for allowing the plug to move through restricted areas or bends in the tubes. This invention further allows single replacement of worn scraper elements rather than requiring replacement of an entire plug whenever a scraper element experiences wear.